On Fri, Apr 01, 2016 at 02:34:54PM +0800, Qu Wenruo wrote:
> From: Wang Xiaoguang <wangxg.fnst@xxxxxxxxxxxxxx>
>
> Introduce static function inmem_add() to add hash into in-memory tree.
> And now we can implement the btrfs_dedupe_add() interface.
>
> Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
> Signed-off-by: Wang Xiaoguang <wangxg.fnst@xxxxxxxxxxxxxx>
> ---
> fs/btrfs/dedupe.c | 151 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 151 insertions(+)
>
> diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
> index 2211588..4e8455e 100644
> --- a/fs/btrfs/dedupe.c
> +++ b/fs/btrfs/dedupe.c
> @@ -32,6 +32,14 @@ struct inmem_hash {
> u8 hash[];
> };
>
> +static inline struct inmem_hash *inmem_alloc_hash(u16 type)
> +{
> + if (WARN_ON(type >= ARRAY_SIZE(btrfs_dedupe_sizes)))
> + return NULL;
> + return kzalloc(sizeof(struct inmem_hash) + btrfs_dedupe_sizes[type],
> + GFP_NOFS);
> +}
> +
> static int init_dedupe_info(struct btrfs_dedupe_info **ret_info, u16 type,
> u16 backend, u64 blocksize, u64 limit)
> {
> @@ -152,3 +160,146 @@ enable:
> fs_info->dedupe_enabled = 1;
> return ret;
> }
> +
> +static int inmem_insert_hash(struct rb_root *root,
> + struct inmem_hash *hash, int hash_len)
> +{
> + struct rb_node **p = &root->rb_node;
> + struct rb_node *parent = NULL;
> + struct inmem_hash *entry = NULL;
> +
> + while (*p) {
> + parent = *p;
> + entry = rb_entry(parent, struct inmem_hash, hash_node);
> + if (memcmp(hash->hash, entry->hash, hash_len) < 0)
> + p = &(*p)->rb_left;
> + else if (memcmp(hash->hash, entry->hash, hash_len) > 0)
> + p = &(*p)->rb_right;
> + else
> + return 1;
> + }
> + rb_link_node(&hash->hash_node, parent, p);
> + rb_insert_color(&hash->hash_node, root);
> + return 0;
> +}
> +
> +static int inmem_insert_bytenr(struct rb_root *root,
> + struct inmem_hash *hash)
> +{
> + struct rb_node **p = &root->rb_node;
> + struct rb_node *parent = NULL;
> + struct inmem_hash *entry = NULL;
> +
> + while (*p) {
> + parent = *p;
> + entry = rb_entry(parent, struct inmem_hash, bytenr_node);
> + if (hash->bytenr < entry->bytenr)
> + p = &(*p)->rb_left;
> + else if (hash->bytenr > entry->bytenr)
> + p = &(*p)->rb_right;
> + else
> + return 1;
> + }
> + rb_link_node(&hash->bytenr_node, parent, p);
> + rb_insert_color(&hash->bytenr_node, root);
> + return 0;
> +}
> +
> +static void __inmem_del(struct btrfs_dedupe_info *dedupe_info,
> + struct inmem_hash *hash)
> +{
> + list_del(&hash->lru_list);
> + rb_erase(&hash->hash_node, &dedupe_info->hash_root);
> + rb_erase(&hash->bytenr_node, &dedupe_info->bytenr_root);
> +
> + if (!WARN_ON(dedupe_info->current_nr == 0))
> + dedupe_info->current_nr--;
> +
> + kfree(hash);
> +}
> +
> +/*
> + * Insert a hash into in-memory dedupe tree
> + * Will remove exceeding last recent use hash.
> + *
> + * If the hash mathced with existing one, we won't insert it, to
> + * save memory
> + */
> +static int inmem_add(struct btrfs_dedupe_info *dedupe_info,
> + struct btrfs_dedupe_hash *hash)
> +{
> + int ret = 0;
> + u16 type = dedupe_info->hash_type;
> + struct inmem_hash *ihash;
> +
> + ihash = inmem_alloc_hash(type);
> +
> + if (!ihash)
> + return -ENOMEM;
> +
> + /* Copy the data out */
> + ihash->bytenr = hash->bytenr;
> + ihash->num_bytes = hash->num_bytes;
> + memcpy(ihash->hash, hash->hash, btrfs_dedupe_sizes[type]);
> +
> + mutex_lock(&dedupe_info->lock);
Can you describe somewhere in a comment why we need this mutex? It is
unclear just based on reading the code why we need a sleeping lock here.
--Mark
--
Mark Fasheh
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